The present invention relates generally to a method of reducing erosion caused by slurries flowing through transport devices and more particularly to a method of injecting a liquid along the inner surface of a conveying apparatus or spray nozzle to reduce the erosion thereof.
Erosion of piping systems and other known conveying apparatus for slurries is a known problem in the art. However, slurries are increasingly used today to transport and process numerous abrasive solids such as ash, sand, coal and other minerals. Slurry pipelines are being seriously proposed as being an economically advantageous alternative to transporting coal by rail. Slurries are also being prepared for coal liquefiction and as novel fuels for engines. However, the erosion of the slurry pipelines and components is a serious problem which normally results in the premature failure of the pipeline thereby negatively effecting the economics involved in implementing slurries for such new useful purposes.
Erosion or scouring normally occurs when the abrasive slurry particles interact through impaction with the inner pipeline walls. Attempts at solving this known problem have included the use of pipelines constructed of tungsten carbide and other more resistive materials. However, such attempts have not solved the problem because these strong materials are also known to erode over time. Additionally, the use of a thicker piping section or harder materials does not necessarily solve the problem since certain piping sections such as elbows and nozzles require the maintenance of the inside surface of the piping section in order to maintain the proper performance of that particular section. Other early attempts at solving the problem such as those disclosed in U.S. Pat. No. 584,968, Taylor or U.S. Pat. No. 3,149,885, Walsh also fall short of a complete solution. Taylor teaches a method of injecting a stream of water through a single inlet placed at an acute angle to a bend in an attempt to prevent contact of abrasive particles with the upper portion of the bend. Walsh teaches a method for injecting air into the bent portion of tubing for the same purpose. Both inventions are limited in their disclosures to preventing erosion in bent sections of tubing in which only a single wall is protected against the abrasive effects of the solid materials being conveyed therethrough.
Therefore, there is a need for a method and apparatus which prevents the erosion of the entire inner surface area of a pipeline or similar conveying system and which also may be employed to prevent erosion in spray nozzles, manifolds, jet pumps, and other devices commonly used in slurry transport systems.